What telescope are you using it with?
Like Jeanette said, it might not be coming to focus. Best bet is to try it during the day on a far away tree or mountain - if you can't get it come to focus during the day, it won't be able to at night either.
Also like Jeanette said (full of wisdom is she!), an extension tube or a barlow will probably help if focus is the issue.
Also, you can throw away (or at least, stop using

) the moon filter. With the web cam, you can adjust the exposure on the bright parts of the moon (ie: use a shorter exposure).